Validity and reliability of a modified English version of the Physical Activity Questionnaire for Adolescents

Background: Adaptation of physical activity self-report questionnaires is sometimes required to reflect the activity behaviours of diverse populations. The processes used to modify self-report questionnaires though are typically underreported. This two-phased study used a formative approach to investigate the validity and reliability of the Physical Activity Questionnaire for Adolescents (PAQ-A) in English youth. Phase one examined test content and response process validity and subsequently informed a modified version of the PAQ-A. Phase two assessed the validity and reliability of the modified PAQ-A. Methods: In phase one, focus groups (n=5) were conducted with adolescents (n=20) to investigate test content and response processes of the original PAQ-A. Based on evidence gathered in phase one, a modified version of the questionnaire was administered to participants (n=169, 14.5±1.7 years) in phase two. Internal consistency and test-retest reliability were assessed using Cronbach’s alpha and intra-class correlations, respectively. Spearman correlations were used to assess associations between modified PAQ-A scores and accelerometer-derived physical activity, self-reported fitness and physical activity self-efficacy. Results: Phase one revealed that the original PAQ-A was unrepresentative for English youth and that item comprehension varied. Contextual and population/cultural-specific modifications were made to the PAQ-A for use in the subsequent phase. In phase two, modified PAQ-A scores had acceptable internal consistency (α=0.72) and test-retest reliability (ICC=0.78). Modified PAQ-A scores were significantly associated with objectively assessed moderate-to-vigorous physical activity (r=0.39), total physical activity (r=0.42), self-reported fitness (r=0.35), and physical activity self-efficacy (r=0.32) (p≤0.01). Conclusions: The modified PAQ-A had acceptable internal consistency and test-retest reliability. Modified PAQ-A scores displayed weak-to-moderate correlations with objectively measured physical activity, self-reported fitness, and self-efficacy providing evidence of satisfactory criterion and construct validity, respectively. Further testing with more diverse English samples is recommended to provide a more complete assessment of the tool

Trajectories of physical activity from midlife to old age and associations with subsequent cardiovascular disease and all-cause mortality.

INTRODUCTION: It is well established that physical activity (PA) protects against mortality and morbidity, but how long-term patterns of PA are associated with mortality and cardiovascular disease (CVD) remains unclear. METHODS: 3231 men recruited to the British Regional Heart Study, a prospective cohort study, reported usual PA levels at baseline in 1978-1980 (aged 40-59 years) and at 12-year, 16-year and 20-year follow ups. Twenty-year trajectories of PA, spanning from 1978/1980 to 2000, were identified using group-based trajectory modelling. Men were subsequently followed up until 30 June 2016 for mortality through National Health Service central registers and for non-fatal CVD events through primary and secondary care records. Data analyses were conducted in 2019. RESULTS: Three PA trajectories were identified: low/decreasing (22.7%), light/stable (51.0%) and moderate/increasing (26.3%). Over a median follow-up of 16.4 years, there were 1735 deaths. Compared with the low/decreasing group, membership of the light/stable (HR 0.83, 95% CI 0.74 to 0.94) and moderate/increasing (HR 0.76, 95% CI 0.66 to 0.88) groups was associated with a lower risk of all-cause mortality. Similar associations were observed for CVD mortality, major coronary heart disease and all CVD events. Associations were only partially explained by a range of confounders. Sensitivity analyses suggested that survival benefits were largely driven by most recent/current PA. CONCLUSIONS: A dose-response relationship was observed, with higher levels of PA from midlife to old age associated with additional benefits. However, even fairly modest and sustained PA was protective and may be more achievable for the most inactive

Association Between 20-Year Trajectories of Nonoccupational Physical Activity From Midlife to Old Age and Biomarkers of Cardiovascular Disease: A 20-Year Longitudinal Study of British Men

The trajectories of physical activity (PA) from midlife into old age and their associations with established and novel cardiovascular disease (CVD) risk factors in later life remain unclear. This study examined associations between 20-year non-occupational PA trajectories and a range of CVD biomarkers at 60-79 years. 3,331 men (mean baseline age = 50.2 ± 5.8 years) recruited in 1978-80 were followed up after 12, 16 and 20 years, reporting habitual non-occupational PA at each wave. At the 20-year follow up, surviving men attended a physical examination and provided a fasting blood sample. Group-based trajectory modelling was used to identify trajectories. Adjusted regression analyses examined the association between trajectory group membership and several cardiometabolic, cardiac and inflammatory markers at follow up. Three distinct 20-year trajectories were identified: low decreasing (21.3%), light stable (51.8%) and moderate increasing (27.0%). Compared to the low decreasing group, membership of the light stable and moderate increasing trajectory groups was associated with a more favorable cardiometabolic profile, lower levels of inflammation and endothelial dysfunction. Although following a moderate increasing PA trajectory was most favorable, more modest but sustained doses of PA into old age may be sufficient to lower CVD risk

Twenty-Year Trajectories of Physical Activity Types from Midlife to Old Age.

PURPOSE: Correlates of physical activity (PA) vary according to type. However, predictors of long-term patterns of PA types into old age are unknown. This study aimed to identify 20-yr trajectories of PA types into old age and their predictors. METHODS: Seven thousand seven hundred thirty-five men (age, 40-59 yr) recruited from UK towns in 1978 to 1980 were followed up after 12, 16, and 20 yr. Men reported participation in sport/exercise, recreational activity and walking, health status, lifestyle behaviors and socio-demographic characteristics. Group-based trajectory modeling identified the trajectories of PA types and associations with time-stable and time-varying covariates. RESULTS: Men with ≥3 measures of sport/exercise (n = 5116), recreational activity (n = 5085) and walking (n = 5106) respectively were included in analyses. Three trajectory groups were identified for sport/exercise, four for recreational activity and three for walking. Poor health, obesity and smoking were associated with reduced odds of following a more favorable trajectory for all PA types. A range of socioeconomic, regional and lifestyle factors were also associated with PA trajectories but the magnitude and direction were specific to PA type. For example, men with manual occupations were less likely to follow a favorable sport/exercise trajectory but more likely to follow an increasing walking trajectory compared to men with nonmanual occupations. Retirement was associated with increased PA but this was largely due to increased sport/exercise participation. CONCLUSIONS: Physical activity trajectories from middle to old age vary by activity type. The predictors of these trajectories and effects of major life events, such as retirement, are also specific to the type of PA

Tracking of sport and exercise types from midlife to old age: a 20-year cohort study of British men.

Background: Previous physical activity (PA) tracking studies have examined the stability of overall PA and/or PA types, but few have investigated how specific types of sport/exercise track over the life course. The aim of this study was to determine how specific sports/exercises in midlife track and predict future sport/exercise and PA in men transitioning to old age. Methods: Seven thousand seven hundred thirty-five men (aged 40-59 years) recruited in 1978-80 were followed up after 12, 16 and 20 years. At each wave men self-reported participation in sport/exercise. Frequent sport/exercise participants (> 1/month) reported the types of sport/exercise they engaged in. Men also reported total PA, health status, lifestyle behaviours and socio-demographic characteristics. Stability of each sport/exercise was assessed using kappa statistics and intraclass correlation coefficients. Logistic regression estimated the odds of participating in sport/exercise and being active at 20-year follow up according to specific types of sport/exercise in midlife. Results: Three thousand three hundred eighty-four men with complete data at all waves were included in analyses. Tracking of specific sports/exercises ranged from fair to substantial, with golf being the most common and most stable. Bowls was the most frequently adopted. Odds of participating in sport/exercise and being active in old age varied according to sport/exercise types in midlife. Golf and bowls in midlife were the strongest predictors of sport/exercise participation in old age. Golf, cricket and running/jogging in midlife were among the strongest predictors of being active in old age. Compared to participating in just one sport/exercise in midlife, sampling multiple sports/exercises was more strongly associated with sport/exercise participation and being active in old age. Conclusion: The stability of sport/exercise participation from midlife to old age varies by type. Specific sports/exercises in midlife may be more likely to predict future PA than others. However, participating in a range of sports/exercises may be optimal for preserving PA into old age

Global metabolic response of Enterococcus faecalis to oxygen

Oxygen and oxidative stress have become relevant components in clarifying the mechanism that weakens bacterial cells in parallel to the mode of action of bactericidal antibiotics. Given the importance of oxidative stress in the overall defense mechanism of bacteria and their apparent role in the antimicrobial mode of action, it is important to understand how bacteria respond to this stress at a metabolic level. The aim of this study was to determine the impact of oxygen on the metabolism of the facultative anaerobe Enterococcus faecalis using continuous culture, metabolomics and 13C-enrichment of metabolic intermediates. When E. faecalis was rapidly transitioned from anaerobic to aerobic growth, cellular metabolism was directed towards intracellular glutathione production and glycolysis was upregulated two-fold, which increased the supply of critical metabolite precursors (e.g. glycine and glutamate) for sulfur metabolism and glutathione biosynthesis as well as reducing power for cellular respiration in the presence of haemin. The ultimate metabolic response of E. faecalis to an aerobic environment was the upregulation of fatty acid metabolism and benzoate degradation, which was linked to important changes in the bacterial membrane composition as evidenced by changes in membrane fatty acid composition and the reduction of membrane-associated demethylmenaquinone. These key metabolic pathways associated with the response of E. faecalis to oxygen may represent potential new targets to increase the susceptibility of this bacterium to bactericidal drugs.This work was funded by the HRC (Health and Research Council of New Zealand) and the FCT (Portuguese Foundation for Science and Technology), with grant reference SFRH/BD/47016/2008

Camden active spaces: does the construction of active school playgrounds influence children's physical activity levels? A longitudinal quasi-experiment protocol.

Physical activity is essential for every facet of children's health. However, physical activity levels in British children are low. The school environment is a promising setting to increase children's physical activity but limited empirical evidence exists on how a change in the outdoor physical school environment influences physical activity behaviour. The London Borough of Camden is redesigning seven existing school playgrounds to engage children to become more physically active. The primary aim of this project is to evaluate the impact of the redesigned playgrounds on children's physical activity, well-being and physical function/fitness

Investigation of faecal volatile organic compounds as biomarkers for the diagnosis of necrotising enterocolitis

Necrotising enterocolitis (NEC) is the most prevalent and harmful illness in the neonatal intensive care unit. It primarily affects premature babies, with higher incidence in low birthweight patients. NEC usually occurs in the early days of life and may develop rapidly. Its diagnosis is based on medical observation because no early diagnostic tool is currently available. Over the last two decades, developments in analytical chemistry have allowed scientists to perform untargeted investigation of biological samples. Biomarkers are being sought, for a range of disorders, by investigating volatile organic compounds (VOCs) in bio-fluids. For the analysis of gas samples, solid phase micro-extraction (SPME) is a suitable technique to preconcentrate volatile compounds prior to analysis using devices such as gas chromatography – mass spectrometry (GC–MS). Recently, much attention has been directed towards the development of sensors and electronic noses to be used as diagnostic tools in hospitals, as they are generally more compact than a GC-MS and do not require specialised personnel. The work presented here is based on the hypothesis that faeces from patients suffering from necrotising enterocolitis show a specific pattern of volatile organic compounds in the days prior to diagnosis when compared with faeces from healthy patients. The objectives of this work were to develop two methods for the analysis of premature faeces using headspace–SPME–GC–MS and headspace – gas chromatography – sensor (HS–GC–Sensor), to analyse samples from healthy premature infants and premature infants affected by NEC using both instruments and to analyse the data collected. Methods were developed individually for each analytical technique. Two pipelines were applied for mass spectrometric data analysis while classification models were exclusively built using sensor data. Results obtained from HS–SPME–GC–MS data showed that the age at sampling had an influence on the number of compounds identified and on their intensities or relative abundance. Heptanal, 2-E-pentenal, hexanal and 2-methylbutanoic acid were identified as relevant compounds. Classifiers were built at days 1 to 6 prior to diagnosis. Accuracy, sensitivity and specificity of up to 74%, 62% and 79%, respectively, were obtained one day prior to diagnosis based on mass spectrometric data, while accuracy, sensitivity and specificity of 100% were obtained based on sensor data at two days prior to diagnosis. Therefore, classification of samples based on headspace analysis of faeces might have potential for the early diagnosis of necrotising enterocolitis